Here are the things I like about DE.
1. VERY deep world -- a completely new model of reality, a full global history, and a full metaphysics -- that still maps to ideas I understand (alcoholism, socialist revolution).
2. Deep understanding of human thought and human nature. The problems are real, existential, and life-changing. The inner voices mechanism is powerful.
3. The array of characters and spaces to explore is really broad. It's worth the time to visit the different parts of the world.